Snap action switch

Abstract

A micro-switch having an actuating mechanism comprising a pusher bearing directly on a conductive contact carrying spring blade which is trap mounted and pivotable at an anchor point distal from said contact(s), and a lever actuator hinge mounted to the switch case by means of laterally projecting trunnions having flat portions which are pivotable on fulcrum pivot points formed integrally in spaced axially aligned alcove portions in the switch case.

I claim: 
     
       1. A snap action switch, in combination comprising: a case of electrical insulating material having a pair of projecting spaced apart parallel wall portions, and having an opening for access to the interior of said case disposed between said wall portions, said wall portions each having an alcove with a fulcrum pivot formed integrally therein;   a first fixed contact;   a second fixed contact spaced from and opposed to the first contact;   a first and second spaced transversely apart fixed fulcrum legs each having a transverse groove opening away from said fixed contacts;   a third fixed fulcrum leg having a transverse groove opening toward the fixed contacts and disposed between the fixed contacts and said first and second fulcrum legs;   an integral spring sheet metal snap spring blade comprising two elongated longitudinally extending arms spaced transversely apart, and first and second transverse portions each interconnecting said arms at one end of said blade opposite from the other, said second transverse portion having a tongue projecting therefrom toward said first transverse portion and disposed between said arms, said tongue having a bearing edge disposed transversely of the blade and exposed toward said first transverse portion, contact means fixed to said second transverse portion and having first and second contact surfaces each facing away from a different side of said blade, and elongate shank portion extending from said first transverse portion having a width less than the distance between said first and second leg, said shank portion having an end with two laterally extending trunnions each having a bearing edge pivotally retained in a respective groove of said first and second legs with said bearing edge of the tongue being retained in the groove of said third leg, said blade is configured so that its tongue portion is generally rigid and has a bearing edge for being disposed in the groove of said third leg with the bearing edges of said trunnions being disposed in the respective grooves of the first and second legs thereby trap mounting the blade with said first and second contact surfaces being disposed between the fixed contacts;   a pusher device bearing on the shank portion of the blade and having an actuating portion projecting from said opening in the case between said parallel wall portions; and   a flat lever arm having a first and second trunnion extending laterally therefrom each rotatably into a different one of said alcoves and having a flat portion being pivotable on a respective fulcrum pivot point in operative association therewith thereby hinge mounting said lever to the case, said lever having an actuating end portion.   
     
     
       2. A switch comprising: a casing;   a first contact mounted within the interior space of the casing;   a unitary support means comprising a terminal portion without said casing, a base portion disposed longitudinally within the interior space of said switch, a first portion disposed normal to and at one end of said base portion and having a slot therein a second and a third portion spaced apart and normal to said base portion at the other end thereof with each said second and third portions having a slot therein;   a blade means mounted with spring tension to said support means and comprising a contact carrying end free to move within the interior space of said casing, two spaced apart formed spring tension arm portions interconnected at their respective ends by a first and a second transverse portion, a rigid tongue portion integral with said first transverse portion and disposed between said arm portions and terminating in a bearing edge, and a shank portion integral with said second transverse portion with two laterally extending trunnion portions at its other end;   said blade means being mountable to said support means with said bearing edge of said tongue being held in said slot of said first portion while said laterally extending portions of said shank portions are pivotally disposed within a respective slot of the second and third portions of said support means to thereby retain the blade means mounted with the spring tension of said arm portions; and   actuating means operatively associated with said blade means to actuate the free end thereof toward and away from said first contact to make and break contact therewith.   
     
     
       3. A switch as in claim 2, wherein: said shank portion of said blade is formed to establish a corner/knife edge on said trunnion members in the plane of the tensile load, said corner is configured to be pivotally urged against the adjacent oblique corner of the respective slots of said second and third portions of said support means.   
     
     
       4. A switch as in claim 3, and said casing having two fulcrum pivot points each integrally formed in a respective recess in the casing; and   said actuating means including a lever actuator having axially aligning trunnions extending laterally therefrom each having a flat portion pivotable on a respective one of said fulcrum pivot points and a pusher element operatively associated with said blade means and said lever actuator to actuate the free end thereof toward and away from said first contact to make and break contact therewith.   
     
     
       5. A switch as in claim 4, wherein; said casing includes two spaced apart generally parallel wall portions each having a formed recess containing at least one fulcrum pivot point; and   said actuating means includes a lever actuator having axially aligned trunnions extending laterally therefrom each rotatably into one of said recesses and having a flat portion pivotally associated with a fulcrum pivot point within the respective recess, and a pusher element operatively associated with said lever actuator.   
     
     
       6. A switch as in claim 5, wherein: the casing is of plastic material having the fulcrum pivot points formed integrally therein.   
     
     
       7. A switch as in claim 6, wherein: the lever actuator is a generally elongate flat shaped metallic lever device having said trunnions at one end and its other end being selectively actuatable.